Messages in this thread | | | Subject | Re: [PATCH 1/2] ipmi_ssif: Unregister i2c device only if created by ssif | From | Corey Minyard <> | Date | Fri, 24 Aug 2018 08:07:44 -0500 |
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On 08/24/2018 06:10 AM, George Cherian wrote: > In ssif_probe error path the i2c client is left hanging, so that > ssif_platform_remove will remove the client. But it is quite > possible that ssif would never call an i2c_new_device. > This condition would lead to kernel crash as below. > To fix this leave only the client ssif registered hanging in error > path. All other non-registered clients are set to NULL.
I'm having a hard time seeing how this could happen.
The i2c_new_device() call is only done in the case of dmi_ipmi_probe (called from ssif_platform_probe) or a hard-coded entry. How does ssif_platform_remove get called on a device that was not registered with ssif_platform_probe?
Small style comment inline...
> CPU: 107 PID: 30266 Comm: rmmod Not tainted 4.18.0+ #80 > Hardware name: Cavium Inc. Saber/Saber, BIOS Cavium reference firmware version 7.0 08/04/2018 > pstate: 60400009 (nZCv daif +PAN -UAO) > pc : kernfs_find_ns+0x28/0x120 > lr : kernfs_find_and_get_ns+0x40/0x60 > sp : ffff00002310fb50 > x29: ffff00002310fb50 x28: ffff800a8240f800 > x27: 0000000000000000 x26: 0000000000000000 > x25: 0000000056000000 x24: ffff000009073000 > x23: ffff000008998b38 x22: 0000000000000000 > x21: ffff800ed86de820 x20: 0000000000000000 > x19: ffff00000913a1d8 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 > x15: 0000000000000000 x14: 5300737265766972 > x13: 643d4d4554535953 x12: 0000000000000030 > x11: 0000000000000030 x10: 0101010101010101 > x9 : ffff800ea06cc3f9 x8 : 0000000000000000 > x7 : 0000000000000141 x6 : ffff000009073000 > x5 : ffff800adb706b00 x4 : 0000000000000000 > x3 : 00000000ffffffff x2 : 0000000000000000 > x1 : ffff000008998b38 x0 : ffff000008356760 > Process rmmod (pid: 30266, stack limit = 0x00000000e218418d) > Call trace: > kernfs_find_ns+0x28/0x120 > kernfs_find_and_get_ns+0x40/0x60 > sysfs_unmerge_group+0x2c/0x6c > dpm_sysfs_remove+0x34/0x70 > device_del+0x58/0x30c > device_unregister+0x30/0x7c > i2c_unregister_device+0x84/0x90 [i2c_core] > ssif_platform_remove+0x38/0x98 [ipmi_ssif] > platform_drv_remove+0x2c/0x6c > device_release_driver_internal+0x168/0x1f8 > driver_detach+0x50/0xbc > bus_remove_driver+0x74/0xe8 > driver_unregister+0x34/0x5c > platform_driver_unregister+0x20/0x2c > cleanup_ipmi_ssif+0x50/0xd82c [ipmi_ssif] > __arm64_sys_delete_module+0x1b4/0x220 > el0_svc_handler+0x104/0x160 > el0_svc+0x8/0xc > Code: aa1e03e0 aa0203f6 aa0103f7 d503201f (7940e280) > ---[ end trace 09f0e34cce8e2d8c ]--- > Kernel panic - not syncing: Fatal exception > SMP: stopping secondary CPUs > Kernel Offset: disabled > CPU features: 0x23800c38 > > Signed-off-by: George Cherian <george.cherian@cavium.com> > --- > drivers/char/ipmi/ipmi_ssif.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c > index 18e4650..ccdf6b1 100644 > --- a/drivers/char/ipmi/ipmi_ssif.c > +++ b/drivers/char/ipmi/ipmi_ssif.c > @@ -181,6 +181,7 @@ struct ssif_addr_info { > struct device *dev; > struct i2c_client *client; > > + bool client_registered; > struct mutex clients_mutex; > struct list_head clients; > > @@ -1658,6 +1659,8 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id) > * the client like it should. > */ > dev_err(&client->dev, "Unable to start IPMI SSIF: %d\n", rv); > + if (!addr_info->client_registered) > + addr_info->client = NULL; > kfree(ssif_info); > } > kfree(resp); > @@ -1672,11 +1675,14 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id) > static int ssif_adapter_handler(struct device *adev, void *opaque) > { > struct ssif_addr_info *addr_info = opaque; > + struct i2c_client *client; > > if (adev->type != &i2c_adapter_type) > return 0; > > - i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo); > + client = i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo); > + if (client) > + addr_info->client_registered = true; >
How about.. if (i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo)) addr_info->client_registered = true;
No need for the client variable.
-corey
> if (!addr_info->adapter_name) > return 1; /* Only try the first I2C adapter by default. */
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